import sys
n = int(sys.stdin.readline())
def move(N, start, to):
print(start, to)
def hanoi(N, start, to, via):
if N == 1:
move(1, start, to)
else:
hanoi(N-1, start, via, to)
move(N, start, to)
hanoi(N-1, via, to, start)
print(2**n-1)
hanoi(n, 1, 3, 2)